I think my A/C Compressor clutch is nearing the end of its life. Occasionally I'll notice a very slight vibration. I can't actually feel it, but I can see it in the reflection in my rear-view mirror when at a stop light. I've noticed that if I turn on the A/C, vibration goes away. Turn A/C off, and vibration comes back most of the time.

Anybody have any thoughts?